(under subclass 326) Electrodes which are either, (1) filaments, or (2) of the type which are designed to be heated by the flow of electric current through the electrode.
(1) Note. For the other classes which provide for filaments and resistance heated electrodes including those for use in electric lamps and discharge devices, and for the processes and apparatus for making filaments and resistance heated electrodes, see the class definition.
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271+, for devices under the class definition which have a filament and which have supporting and/or spacing structure for the filament.
310, and the subclasses specified in the notes thereto for discharge devices which are provided with a filament or resistance heated cathode.
315+, for incandescent lamps with filaments or resistance heated glowers. 336, where the electrode is electron emissive, the electrode being designed so that the electron emission is restricted to a point-like area.
337+, and the subclasses specified in the notes thereto where the electrode is an indirectly heated cathode, that is, the cathode includes an electron emissive part and a separate heating means to heat the emissive part to the electron emitting temperature.
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428, Stock Material or Miscellaneous Articles,
364+, for a filament which is coated or is structurally defined, but omits structure (e.g., terminals or leads), which defines an electrode for Class 313 or a product elsewhere classified.
